Data type mismatch in criteria expression exception in ms acess database

Question

I'm creating a simple program about now the idea is to insert the data "Person information Name, Age ETC. " inside the database through my c# program and I when I click the button I get this error

System.Data.OleDb.OleDbException (0x80040E07): Data type mismatch in criteria expression. at System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(OleDbHResult hr) at System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(tagDBPARAMS dbParams, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommandText(Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteCommand(CommandBehavior behavior, Object& executeResult) at System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) at System.Data.OleDb.OleDbCommand.ExecuteNonQuery() at School_System.newRegisteration.button1_Click(Object sender, EventArgs e) in C:\\Users\\OmarS_000\\documents\\visual studio 2015\\Projects\\School System\\School System\\newRegisteration.cs:line 35

Here is my code

   using System;
   using System.Collections.Generic;
   using System.ComponentModel;
   using System.Data;
   using System.Drawing;
   using System.Linq;
   using System.Text;
   using System.Threading.Tasks;
   using System.Windows.Forms;
   using System.Data.OleDb;
   using System.ComponentModel;


  public partial class newRegisteration : Form

               {
            private OleDbConnection connection = new OleDbConnection();
            public newRegisteration()
            {
                InitializeComponent();
                connection.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\OmarS_000\Documents\Visual Studio 2015\Projects\School System\School System\School.accdb;
    Persist Security Info=False;";
            }

            private void button1_Click(object sender, EventArgs e)
            {
                try
                {
                    connection.Open();
                    OleDbCommand command = new OleDbCommand();
                    command.Connection = connection;
                    command.CommandText = "INSERT into School ([Name], [Age], [Grade], [Class]) VALUES('" + nameTextBox2 + "', '" + ageTextBox2 + "', '" + gradeTextBox2 + "', '" + classTextBox2 + "') ";

                    command.ExecuteNonQuery();
                    MessageBox.Show("Data Saved");
                    connection.Close();
                }
                catch (Exception ex)
                {
                    MessageBox.Show("Error" + ex);
                }
            }
              }

line 35 which the error mentioned it contains

command.ExecuteNonQuery();

i get this error when i click on the button, but the codes in the visual studio debugs perfectly with 0 errors. so what spot did i miss right here ?

Answer 1

您正在使用某些文本框中的值，因此需要使用其Text属性来获取值

command.CommandText = "INSERT into School ([Name], [Age], [Grade], [Class]) VALUES('" + nameTextBox2.Text + "', '" + ageTextBox2.Text + "', '" + gradeTextBox2.Text + "', '" + classTextBox2.Text + "') ";